IPhone could not be restored an unknown error occurred (40).

Asked By 40 points N/A Posted on -

Hi Pro,

I think I made some terrible mistake while updating my iPhone. The Problem is when I try to update my iTunes; all of a sudden, it crashed so I try to download it again. I am not able to complete the process. I am getting this below error message repeatedly. How do I restore my iPhone? Please help me to solve this problem. Thanks a lot.


The iPhone “iPhone” could not be restored. An unknown error occurred (40). 

Answered By 70 points N/A #173174

IPhone could not be restored an unknown error occurred (40).


iTunes is the perfect way to upgrade your iPhone. Sometimes, it might give you some issue. This issue is hard to fix not impossible.

First, check if your firewall or similar software is blocking the internet connection of iTunes. Disable your firewall and antivirus, then try to restore again.

Secondly, try the latest version of iTunes. It is very important because latest versions come with various known environment and works better with improved fixes. Download iTunes.

You can also try manually putting them in DFU mode.

  1. Press and hold the “Home” button and “Sleep/Wake” button together for 10 seconds.
  2. Start iTunes in your PC.
  3. Connect iTunes to your PC. It will say that an iPhone is detected which is on recovery mode.

Now, try to restore your iPhone.

Also, check the “hosts” file inside your Windows system.

  1. Start Notepad with administrative privilege.
  2. Open the file “C:WindowsSystem32driversetchosts”.
  3. Find out any line that matches any server(s) listed here.

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